Aluminized surface to improve solar light absorption in open reactors: Application for micropollutants removal in effluents from municipal wastewater treatment plants

This work proposes the evaluation of an aluminized surface on the bottom of open reactors to perform a photo-Fenton process, at circumneutral pH (using Fe III-Ethylenediamine-N,N'-disuccinic acid complex), for elimination of micropollutants (MPs) in real effluents from municipal wastewater treatment plants (EMWWTP). Firstly, the strategy was to initially investigate the real EMWWTP spiked with several MPs (acetaminophen, diclofenac, carbamazepine, caffeine, trimethoprim and sulfamethoxazole) with 20 and 100 μg L^-1 in a laboratory scale (evaluated by HPLC-UV) using a solar simulator. Finally, the removal of all MCs present in the real EMWWTP was monitored (evaluated by HPLC-MS) in a pilot-scale (90 L) in a raceway pond reactor (RPR). The treatment time required for degradation above 80% for the investigated MPs was over 30 min, and the predominant effect could be mainly associated with organics present in the real EMWWTP due to the light attenuation and scavenging of radical species. Moreover, the results confirmed that chloride and sulfate would most likely equally not affect the process. The use of an aluminized surface on the bottom of RPRs has been confirmed as a suitable option to improve the photo-Fenton reaction, enabling the use of lower doses of iron. Up to 60 different MPs found in EMWWTP have been successfully degraded using 0.1 mM of Fe at circumneutral pH with a consumption of 30 mg L^-1 H₂O₂ with less than 45 min.